A conventional dumbbell assembly 60 is shown in FIG. 8 and generally includes a bar 61 and multiple disk-like weight members 62 connected to two ends of the bar 61. The bar 61 includes two threaded ends 611 and the weight members 62 are mounted to the two threaded ends 611 and two nuts 612 are respectively and threadedly connected to the two threaded ends 611 to fix the weight members 62.
The conventional dumbbell can be used to exercise the muscles by the assembly of the bar and the weight members, however, the dumbbell assembly can only be used to lift it up and down, which is so boring and the users easily give up.
The present invention intends to provide a dumbbell assembly which includes two disks rotatably connected to two ends of the bar and each disk is optionally connected to at least one weight member. The weight members are eccentrically connected to the disks so that when using the dumbbell assembly, the wings rotate to apply centrifugal forces to the user's muscles.